Electronic device



1967 c. L. SHANO 3,356,896

ELECTRONIC DEVICE Filed Dec. 16, 1964 V 2 Sheets-Sheet 1 52 53{ I fad E age T uvv AIAAA IvIv wchronizer. 511m 22 cwfilll DC TO DC {I5 I? 'ww- 26 Converter l J 0c o c Converter Q VOLTAGE ON COIL 52 l nvenror Charles L. Shano 48 Level D tgl A BISfllblE Switch 1 I Dec. 5, 1967 c. L. SHANO 3,356,896

ELECTRONIC DEVICE Filed Dec. 16, 1964 2 Sheets- Sheet 2 ]To Level Det 87 ]To Level Def 88 'BVE \1 2 Mmy Ill mud/5 FIG. Yv

FIG. 8

To Level Def. 8? 233 To Level Inventor Charles L. Shane United States Patent 3,356,896 ELECTRONIC DEVICE Charles L. Shano, Morton Grove, Ill., assignor to M0- torola, Inc., Franklin Park, 111., a corporation of Illinois Filed Dec. 16, 1964, Ser. No. 418,690 11 Claims. (Cl. 315-409) ABSTRACT OF THE DISCLOSURE In this ignition system, a wedge shaped flux varying element is rotated past a magnetic pickup to induce a voltage in the pickup coil. The induced voltage at a predetermined level is coupled by a level detector to trigger a silicon controlled rectifier which energizes an ignition coil. Electronic advance is provided by the wedge shaped flux varying element inducing voltage in the pickup coil to the predetermined level at different rotational positions of the wedge with respect to the pickup depending on the rate the wedge is rotated by the engine. During engine cranking, a stepped portion is provided on the trailing edge of the element to provide a sudden flux change in order to raise the induced voltage to the predetermined level. Electronic distribution is provided by having a magnetic pickup and level detector for each pair of cylinders, or by using a bistable switch that is responsive to the trigger pulses from the level detector to fire the cylinders in their proper order.

This invention relates to ignition systems for internal combustion engines, and more particularly to an improved ignition system which performs distribution and advance functions by electronic means.

Many ignition systems for internal combustion engines have been proposed which utilize electronic circuitry to produce ignition pulses in an ignition coil. Such systems have significant advantages over systems which utilize mechanical breaker contacts for producing ignition pulses in that they are more reliable, have long operational life, and produce higher voltage pulses at the extreme ends of the speed range over which they operate.

Many of such systems, however, retain mechanical devices for distributing the ignition pulses to the particular cylinders and for advancing the timing of the ignition pulses with respect to engine position. This latter function is desirable because the combustion time in a cylinder remains constant despite higher piston velocities at higher speeds and therefore the beginning of combustion must be adjusted for maximum thrust at the top of the piston travel. Mechanical devices for advance and distribution often present the same drawbacks as did the mechanical breaker contacts insofar as reliability voltage magnitude and operational life are concerned.

It is an object of this invention to provide an ignition system for internal combustion engines which performs the distribution and advance functions electronically.

Another object of the invention is to provide an improved and economical ignition system which advances the ignition pulses electronically.

A feature of the invention is the provision of a pulser for an ignition system which comprises a rotatable member with a flux varying element thereon and a magnetic pick-up disposed adjacent the path of travel of the flux varying element, with the flux varying element being shaped to provide a gap between it and the magnetic pick-up as it passes by the pick-up which diminishes at a predetermined rate for a given rate of member rotation and then which diminishes at a rate substantially greater than the predetermined rate.

3,356,896 Patented Dec. 5, 1967 Another feature of the invention is the provision, in an ignition system for a multi-cylinder internal combustion engine, of an electronic steering circuit for steering ignition pulses to respective ignition devices for the cylinders.

Another feature of the invention is the provision of a pulser, for an ignition system, which has a rotating member with a flux varying element thereon and a plurality of magnetic pick-ups disposed adjacent the path of travel of the rotating member, each of which pick-ups is connected to a respective ignition device, and with the flux varying element being shaped to provide a gap between it and each magnetic pick-up as it passes which diminishes at a predetermined rate for a given rate of rotation and then which diminishes at a rate substantially greater than the predetermined rate.

In the drawings:

FIG. 1 is a schematic diagram of an ignition system constructed in accordance with the invention;

FIG. 2 is an enlarged sectional view of a portion of the pick-up unit and flywheel taken along the line 2-2 of FIG. 1 and with a sectional showing of the flywheel housing added;

FIG. 3 is an enlarged view of the pick-up and flux varying element used in FIG. 1;

FIG. 4 is a graph showing the voltage produced by the pick-up for various engine speeds; and

FIG. 5 is a schematic diagram of an alternative embodiment of the invention.

FIGS. 6 and 7 are elevational views of respective alternative configurations for the pulser used with the circuit of FIG. 5; and

FIG. 8 is a plan view of the engine flywheel of FIG. 7.

The invention comprises an ignition system for an internal combustion engine. It includes an ignition circuit which is responsive to trigger pulses applied thereto to provide sparks for igniting fuel in the internal com-bustion engine. Means are coupled to the ignition circuit for supplying trigger pulses thereto in synchronism with the internal combustion engine. Such means comprise a rotatable member synchronized with the internal combustion engine and having a flux varying element thereon. A magnetic pick-up is disposed adjacent the path of travel of the flux varying element and has an inductance winding producing a voltage in response to changing flux in the magnetic pick-up when the flux varying element passes by. The flux varying element is shaped so that as it passes the pick-up, the gap between it and the pick-up diminishes at a predetermined rate for a given rate of rotation and then diminishes at a rate substantially greater than the predetermined rate. The flux varying element produces a voltage in the inductance winding which rises to a given level at a point during the rotation of the rotatable member which advances with the speed of rotation of the rotatable member. A detector couples the ignition circuit to the inductance winding and is responsive to a voltage produced therein exceeding the given level to produce a trigger pulse for the ignition circuit.

The ignition circuit may comprise a plurality of ignition devices, each operable to produce a spark in a respective cylinder of the internal combustion engine in response to a firing pulse supplied to the ignition device. An electronic steering circuit has an input conductor connected to the detector and a plurality of output conductors, each connected to a respective one of the ignition devices for supplying firing pulses thereto. The electronic steering circuit is responsive to each trigger pulse applied to its input conductor to produce a firing pulse in a successive one of the output conductors for successive operation of the ignition devices.

Alternatively, the invention may comprise a plurality of pick-ups located adjacent the path of the flux varying element. A plurality of detectors couples the pick-ups to respective ignition devices. Thus, the pulse steering or distribution is accomplished by the separate pick-ups.

The circuits shown in FIGS. 1 and 5 are for use with a four cylinder engine with a four stroke cycle. Thus two cylinders will go through their power stroke for each revolution of the engine flywheel. It is to be understood, however, that the ignition system of the invention can be adapted to engines of other numbers of cylinders within the scope of this invention. Each of the cylinders of the engine is provided with a spark gap or spark plug 11-14, and a separate ignition coil 1518. The secondary windings of each of the coils 1518 are connected across respective spark gaps 11-14.

A semiconductor controlled rectifier 21 connects the parallel connected primary windings of ignition coils 15 and 16 in series across an ignition capacitor 22. Similarly a semiconductor controlled rectifier 23 connects the parallel connected primary windings of ignition coils 17 and 18 in series across ignition capacitor 22. A DC to DC converter 24 couples ignition capacitor 22 through ignition switch 25 to a source of DC potential, storage battery 26. Converter 24 steps up the voltage of storage battery 26 to a very high value to charge capacitor 22 between firings of the respective semiconductor controlled rectifiers 21 and 23. Of the two cylinders associated with ignition coils 15 and 16, one is ready to be fired and the other is on exhaust stroke. Thus, only the cylinder to be fired is affected by a pulse through the ignition coils 15 and 16. This is also true of ignition coils 17 and 18. Accordingly, two cylinders at a time are fired, one of which is on exhaust stroke and consequently is not affected.

An electronic steering circuit is used to steer trigger pulses to the proper semiconductor controlled rectifier for firing the proper parallel set of ignition coils. This electronic steering circuit, in the case of the four cylinder engine shown, is bistable switch 31; bistable switch 31 is shown in the drawing comprised of a pair of transistors 32 and 33 interconnected with appropriate resistors, diodes and capacitors to form a flip-flop. Thus conduction of transistor 32 will, while transistor 33 is cut off, provide a pulse across a resistor 34 for triggering semiconductor controlled rectifier 21. Similarly conduction of transistor 33 and cut off of transistor 32 applies a pulse across resistor 35 which triggers semiconductor controlled rectifier 23. Accordingly, bistable switch 31 serves to steer the pulses to the proper set of ignition coils. The switching of bistable switch 31 occurs as a result of switching pulses applied thereto from pulse generator 41. As shown in FIG. 1, pulse generator 41 is an amplifier comprised of common emitter transistor 42 with associated resistors and a coupling capacitor.

Pulse generator 41 is switched on to provide a switching pulse for bistable switch 31 by means of a pulser which operates in synchronism with the internal combustion engine. The pulser comprises a pair of shaped flux varying elements 45 and 46 mounted on the engine flywheel 47. A pick-up unit 48, which may be adjustably mounted on the flywheel housing 49 by a bracket 51 (see FIG. 2), includes an inductance winding 52 surrounding a pole piece 53. Pole piece 53 is disposed so that its tip is adjacent the path of elements 45 and 46. Winding 52 is connected to a level detector 61 comprised of a diode 62 connected across the coil 52 and a zener diode 63.

As flywheel 47 rotates, each of elements 45 and 46, as it passes pole piece 53, will cause a change in flux in winding 52. Flywheel 47 rotates in the direction of the arrow so that the pointed ends of the elements 45 and 46 pass by the pole piece 53 first. In FIG. 3, an enlarged view of element 45 in relation to pole piece 53 is shown. It will be noticed that element 45 has a long arcuate leading portion of a width 0, followed by a small step of a width b. As element 45 moves in the direction of the arrow, the dimension d, that is, the space between the element 45 and the pole piece 53 will decrease at a gradual rate according to the curved surface of element 45. Then, as the step passes by the pole piece 53, the dimension d decreases at a very high rate.

The result of the foregoing described configuration is that the spark will be advanced electronically. Sparking advance is necessary as the engine speed increases because the combustion time in a cylinder remains constant despite higher piston velocities at higher speeds. Therefore, the beginning of combustion must be advanced in relation to piston position (ie engine rotation), so that the maximum thrust occurs at the top of piston travel. The amount and characteristics of the advance may be controlled by the particular shape and size of element 45.

Referring to FIG. 4, the effect of the element 45 on the voltage produced in coil 52 may be seen. The solid line 65 represents the voltage produced in winding 52 when the engine is turning over at cranking or starting speeds. These speeds are very low and accordingly it will be seen that the voltage produced in winding 52 is very low until the rapid change of flux occurs as a result of the passage of the stepped portion of element 45 past pole piece 53. At this time, the voltage will rapidly peak and then decline. In FIG. 4, the angle 0 approximates the angle occupied by the element 45 from its pointed tip to just past the beginning of the stepped portion (see FIG. l), and the voltage E represents the voltage on the coil 52 which must be exceeded to break down zener diode 63 and hence produce an output from level detector 61. It will be seen that level detector 61 will not conduct until quite late in the passage of element 45.

The dot-dash line 66 represents the voltage in winding 52 at engine idle. It will be seen that because the engine is rotating at a slightly faster speed than during cranking, the peak voltage as the step portion of element 45 passes pole piece 53 will be higher. Nevertheless, the rotation is still sufficiently slow that the pulsing of level detector 61 does not occur until the step, and hence quite late in the cycle.

The dot-dot-dash line 67 represents an engine speed of 1,000 r.p.m. At this speed it will be seen that element 45 passes pole piece 53 at a sufficiently high rate of speed that the leading portion ahead of the step will produce enough voltage that the detector level is exceeded much earlier.

An engine speed of 2,000 r.p.m. is represented by the dot line 68 and it will be seen that here even more advance is achieved because of higher engine speeds.

It is essential that synchronization of the ignition pulses with respect to the proper cylinders at the proper time exists. This is accomplished by means of a synchronizer 70 having a magnet 71, located on the underside of the flywheel 47. The magnet is located ahead of the firing position of the first cylinder which is to be fired. The bistable switch 31 and the pulse generator 41 are connected to the power supply, battery 26, through a magnetically actuable reed switch 72. Magnet 71 passes switch 72 just before, and only before, firing of the proper cylinder, that is, the first cylinder to be fired. Accordingly, only when switch 72 is closed, which will only occur at the proper time, will pulse generator 41 and bistable switch 31 be energized. Once switch 72 is closed, a holding coil 73 prevents reopening until ignition switch 25 is opened. A current limiting resistor 74 and a voltage protecting zener diode 75 are provided in the synchronizer circuitry.

In FIG. 5, the circuit shown accomplishes the steering or distribution function without utilizing a bistable switch. In this system, two pick-up units 81 and 82 are used in association with a single flux varying element 83 on the engine flywheel 47. Level detectors 87 and 88 are used in connection with the repective pick-ups 81 and 82. Similarly, separate pulse generators )1 and 92 are utilized to produce trigger pulses for the semiconductor controlled rectifiers 21 and 23. Sufficient voltage may be available at the level detectors such that it would not be necessary to utilize pulse generators. Pulses genera-ted first in pick-up 81 and then in pick-up 82 are detected in respective detectors 87 and 88 and utilized to trigger the respective semiconductor con-trolled rectifiers 21 and 23 at appropriate times. No synchronizing is necessary with this system as there is only a single flux varying element 83. Since element 83 is shaped similarly to elements 45 and 46 in FIG. 1, the pick-up of this system will have the same characteristics, that is, will provide advance electronically.

FIG. 6 shows another type of pulser which may be used with the circuit of FIG. 5. Here, two pick-ups 181 and 182, separated by magnetic shielding 151a, are mounted next to each other on a bracket 151 extending from the flywheel housing 49 and are aligned with each other generally in a plane passing through the axis of rotation of the flywheel 47. The flat face of flywheel 47 is provided with two flux varying elements 183 and 184. Element 183 is positioned to pass pick-up 181, and element 184 is positioned outwardly of flywheel 47 on an extension 185 to pass pick-up 182. Thus, every 180 rotation of flywheel 47 causes one of the element-s 183 and 184 to pass its respective pick-up 181 and 182 and produce a pulse therein.

FIGS. 7 and 8 illustrate still another type of pulser which may be used with the circuit of FIG. 5. Here the flux varying elements 283 and 284, separated by magnetic shielding 251a, are mounted in an attitude rotated 90 from that shown in the other embodiments. Pick-ups 281 and 282 extend from a bracket 251 on flywheel housing 49 toward the face of flywheel 47, and elements 283 and 284 are displaced diflerent distances from the axis of flywheel 47 to align themselves with respective ones of the pickups. Thus, as in FIG. 6, every 180 rotation of flywheel 47 causes one of the elements 283 and 284 to pass its respective pick-up 281 and 282 and produce a pulse therein.

It may therefore be seen that the invention provides an improved ignition system for an internal combustion engine which performs the distribution and advance functions electronically without elaborate circuitry and complex operation.

I claim:

1. An ignition system for an internal combustion engine, including in combination, ignition means responsive to trigger pulses applied thereto to produce sparks for igniting fuel in the internal combustion engine, pulse means coupled to said ignition means for supplying trigger pulses thereto in synchronism with the internal combustion engine, said pulse means comprising a rotatable member synchronized with the internal combustion engine and having a flux varying element thereon, said pulse means further comprising a magnetic pick-up disposed adjacent the path of travel of said flux varying element and having an inductance coil for producing a voltage in response to changing flux in said magnetic pick-up when said flux varying element passes by, said flux varying element having a first shaped portion to provide a gap between it and said magnetic pick-up as it passes by said magnetic pick-up which changes at a predetermined rate for a given rate of rotation, said flux varying element further having a second shaped portion integral with the first shaped portion which changes the gap at a rate substantially greater than said predetermined rate, said flux varying element producing a voltage in said inductance coil which rises to a given level at a rotational position of said rotatable member which varies in accordance with the speed of rotation of said rotatable member, level detector means, and electronic distributing means coupled to said ignition means, said level detector means coupling said inductance coil to said electronic distributing means and being responsive to a voltage produced by said inductance coil at the given level to produce a trigger pulse for said ignition means.

2. The combination of claim 1 wherein said ignition means comprises a plurality of ignition devices, each operable to produce a spark in a respective cylinder of the internal combustion engine in response to a firing pulse applied to the ignition device, and the electronic distributing means includes bistable multivibrator means having an input connected to said level detector means and an output to said ignition means, said bistable multivibrator means being operated by trigger pulses from said detector means to energize said ignition means.

3. The combination of claim 1 wherein said ignition means comprises a plurality of ignition devices, each operable to produce a spark in a respective cylinder of the internal combustion engine in response to a firing pulse applied to said ignition device, and wherein the electronic distributing means includes a plurality of level detectors, and a plurality of semiconductor trigger means each connected to a respective level detector and to a respective one of the ignition devices for supplying firing pulses thereto, said level detectors being responsive to pulses of a predetermined magnitude from said pulse means to gate on the associated semiconductor trigger means to produce firing pulses for synchronized operation of the ignition devices.

4. An ignition system for a multi-cyliuder internal combustion engine, including in combination, a plurality of spark devices one for each cylinder of the internal combustion engine to produce sparks therein for igniting fuel, a plurality of ignition coils, each connected to a respective one of said spark devices and energizable for supplying high voltage spark pulses thereto, said ignition coils comprising two parallel connected groups, a source of potential, a pair of semiconductor controlled rectifiers, each connecting a respective one of said parallel groups of coils in series across said source of potential, pulse producing means operable to produce trigger pulses in synchronism with the internal combustion engine, and a bistable switch having an input conductor connected to said pulse producing means and having first and second output conductors, each connected to a respective one of said semiconductor controlled rectifiers for supplying firing pulses thereto to switch said semiconductor controlled rectifiers on, and energize said group of coils connected thereto, said bistable switch being responsive to each trigger pulse applied thereto by said pulse producing means to produce a firing pulse in a respective one of said output conductors for successive conduction of said semiconductor controlled rectifiers to produce successive spark pulses in each of said groups of ignition coils.

5. The combination of claim 4, wherein said source of potential comprises an ignition capacitor and means for charging the same between firings of said semiconductor controlled rectifiers.

6. An ignition system for a multi-cylinder internal combustion engine including in combination, ignition means resposive to trigger pulses applied thereto to produce sparks for igniting fuel in the cylinders of the internal combustion engine, and pulse means coupled to said ignition means for supplying trigger pulses thereto in synchronism with the internal combustion engine, said pulse means comprising a rotatable member synchronized with the internal combustion engine and having a flux varying element and a permanent magnet thereon, said pulse means further comprising a magnetic pick-up disposed adjacent the path of travel of said flux varying element and having inductance means producing a voltage in response to changing flux in said magnet pick-up when said flux varying element passes by, said flux varying element being shaped to provide a gap between it and said magnetic pick-up as it passes by said magnetic pick-up which diminishes at a predetermined rate for a given rate of engine rotation, and then which diminishes at a rate substantially greater than said predetermined rate, said flux varying element producing a voltage in said inductance means which rises to a given level at a rotational position of said rotatable member which varies in accordance with the speed of rotation of said rotatable member, said pulse means further comprising detector means coupling said inductance means to said ignition means and responsive to a voltage produced by said inductance means exceeding the given level to produce a trigger pulse for said ignition means, an ignition switch for connecting said detector means and said pulse means to a source of potential, and relay means in series with said ignition switch and remaining open to prevent energization of said pulse means and said detector means when said ignition switch is open, said relay means being disposed adjacent said rotatable member and being responsive to passage of said permanent magnet thereby to close, thereby synchronizing operation of said detector means and said pulse means with the position of said rotatable member.

7. In an ignition system for a multi-cylinder internal combustion engine, having ignition means responsive to trigger pulses applied thereto to produce sparks for igniting fuel in the cylinders of the internal combustion engine, the combination including, pulse means coupled to the ignition means for supplying trigger pulses thereto in synchronism with the internal combustion engine, said pulse means comprising a rotatable member synchronized with the internal combustion engine and having a flux varying element thereon, said pulse means further having a magnetic pick-up with a pole piece disposed adjacent the path of travel of said fiux varying element and having an inductance coil producing a voltage in response to changing flux in said magnetic pick-up when said flux varying element passes by said pole piece, said fiux varying element having a leading portion of generally wedgeshaped configuration to provide a gap between said fiux varying element and said pole piece as said flux varying element passes by said pole piece which diminishes at a predetermined rate for a given rate of rotation of said rotatable member, said flux varying element having a stepped portion following said leading portion to diminish the gap between said flux varying element and said pole piece at a rate substantially greater than said predetermined rate, said flux varying element producing a voltage in said inductance means which rises to a given level at a rotational position of said rotatable member which varies in accordance with the speed of rotation of said rotatable member, and level detector means coupling said inductance means to the ignition means and being responsive to a voltage produced by the inductance means exceeding the given level to produce a trigger pulse for said ignition means.

8. An ignition system for a multi-cylinder internal combustion engine, including in combination, a plurality of ignition devices, each operable to produce a spark in a respective cylinder of the internal combustion engine for igniting fuel therein in response to a firing pulse applied to said ignition device, pulse producing means operable to produce trigger pulses in synchronism with the internal combustion engine, electronic steering means including a plurality of level detectors having respective semiconductor pulse generator means connected thereto, and a plurality of semiconductor trigger means each connected to respective semiconductor pulse generator means and to a respective one of the ignition devices for supplying firing pulses thereto, said level detectors being responsive to triggerpulses of a predetermined magnitude from said pulse producing means to gate on said semiconductor pulse generator means associated therewith to operate the associated semiconductor trigger means to produce firing pulses for synchronized operation of the ignition devices.

9. An ignition system for an internal combustion engine, including in combination, ignition means responsive to trigger pulses applied thereto to produce sparks for igniting fuel in the internal combustion engine, pulse means coupled to said ignition means for supplying trigger pulses thereto in synchronism with the internal combustion engine, said pulse means comprising a rotatable member synchronized with the internal combustion engine and having a flat face thereon perpendicular to the axis of rotation of said rotatable member, first and second flux varying elements mounted on said flat face of said rotatable member between the axis thereof and the periphery of said face, said pulse means further comprising first and second magnetic pickups aligned in a plane which contains the axis of rotation of said rotatable member and each having inductance means producing a voltage in response to changing flux in said magnetic pickup with said flux varying element passing by, said first and second flux varying elements being disposed on said rotatable member in position to align themselves with respective ones of said first and second magnetic pickups to pass thereby as said rotatable member rotates, each of said fiux varying elements having a first portion shaped to provide a gap between it and said magnetic pickup aligned therewith as it passes by said magnetic pickup which gap changes at a predetermined rate for a given rate of rotation, and a second portion integral with said first portion and being shaped to change the gap at a rate substantially greater than said predetermined rate, and level detector means coupling said inductance means to said ignition means and being responsive to a voltage produced by said inductance means at a predetermined level to produce a trigger pulse for said ignition means, said first shaped portion of said flux varying elements producing a voltage in said magnetic pickup associated therewith which rises to the predetermined level at a rotational position of said rotatable member which varies in accordance with the speed of rotation of the member with the speed thereof approximately exceeding idling speed, and said second shaped portion producing a voltage in said magnetic pickup associated therewith which abruptly arises to the predetermined level'with the engine being cranked.

10. The combination of claim 9 wherein said first and second pickups are adjacent the periphery of said rotatable member with said second pickup being disposed further from the plane of said flat face than said first pickup, and wherein said second flux varying element is disposed a distance from said face sufiicient to align itself with said second pickup.

11. The combination of claim 9 wherein said pickups are disposed adjacent said fiat face of said rotatable members with said second pickup being disposed further from the axis of rotation of said rotatable member than said first pickup, and wherein said second flux bearing element is disposed a distance from the axis of rotation of said rotatable member sufficient to align itself with said second pickup.

References Cited UNITED STATES PATENTS 3,072,823 1/1963 Kirk 3l5218 3,127,540 3/1964 Collins 315- 3,139,876 7/1964 Jukes 315218 3,222,588 12/1965 Campbell 3 l5-232 3,242,916 3/1966 Coufal 315-209 3,277,875 10/ 1966 Miki 123148 JOHN W. HUCKERT, Primary Examiner.

A. M. LESNIAK, Assistant Examiner. 

1. AN IGNITION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE, INCLUDING IN COMBINATION, IGNITION MEANS RESPONSIVE TO TRIGGER PULSES APPLIED THERETO TO PRODUCE SPARKS FOR IGNITING FUEL IN THE INTERNAL COMBUSTION ENGINE, PULSE MEANS COUPLED TO SAID IGNITION MEANS FOR SUPPLYING TRIGGER PULSES THERETO IN SYNCHRONISM WITH THE INTERNAL COMBUSTION ENGINE, SAID PULES MEANS COMPRISING A ROTATABLE MEMBER SYNCHRONIZED WITH THE INERNAL COMBUSTION ENGINE AND HAVING A FLUX VARYING ELEMENT THEREON, SAID PULSE MEANS FURTHER COMPRISING A MAGNETIC PICK-UP DISPOSED ADJACENT THE PATH OF TRAVEL OF SAID FLUX VARYING ELEMENT AND HAVING AN INDUCTANCE COIL FOR PRODUCING A VOLTAGE IN RESPONSE TO CHANGING FLUX IN SAID MAGNETIC PICK-UP WHEN SAID FLUX VARYING ELEMENT PASSES BY, SAID FLUX VARYING ELEMENT HAVING A FIRST SHAPED PORTION TO PROVIDE A GAP BETWEEN IT AND SAID MAGNETIC PICK-UP AS IT PASSES BY SAID MAGNETIC PICK-UP WHICH CHANGES AT A PREDETERMINED RATE FOR A GIVEN RATE OF ROTATION, SAID FLUX VARYING ELEMENT FURTHER HAVING A SECOND SHAPED PORTION INTEGRAL WITH THE FIRST SHAPED PORTION WHICH CHANGE THE GAP AT A RATE SUBSTANTIALLY GREATER THAN SAID PREDETERMINED RATE, SAID FLUX VARYING ELEMENT PRODUCING A VOLTAGE IN SAID INDUCTANCE COIL WHICH RISES TO A GIVEN LEVEL AT A ROTATIONAL POSITION OF SAID ROTATABLE MEMBER WHICH VARIES IN ACCORDANCE WITH THE SPEED OF ROTATION OF SAID ROTATABLE MEANS COUPLED DETECTOR MEANS, AND ELECTRONIC DISTRIBSUTING MEANS COUPLED TO SAID IGNITION MEANS, SAID LEVEL DETECTOR MEANS COUPLING SAID INDUCTANCE COIL TO SAID ELECTRONIC PRODUCED BY SAID AND BEING RESPONSIVE TO A VOLTAGE PRODUCED BY SAID INDUCTANCE COIL AT THE GIVEN LEVEL TO PRODUCE A TRIGGER PULSE FOR SAID IGNITION MEANS. 